Flame sealing apparatus



Jan, 18, 1949. A. G. HEWITT ETAL I FLAME SEALING APPARATUS 1 .3 Shets-Sheet 1 Filed April 5, 1946 T W 0m M x TAM E r N ETL R V C 0 W T IEF T k A m f .05 E5 a? 3 4/ LY 5 J J ll 7.. Q. 8 I m u\\\ n n a mm 1% a m w 8 HM I I I l g (Q M a \Q Jan; 18, 1949. A. s. HEWITT arm. 2,459,235

J FLAME SEALING APPARATUS Filed April 5. 194s s Sheets-Sheet 2 IN V EN TORS I 'RED G. HEWITT AND YL v53 TER F. CLEMENT ATTORNE M 1949- A. s. HEWITT ,ET AL 2,459,235

FLAME smmne APPARATUS Filed April 5, 1946 v 5 Sheets-Sheet 3 (1'1 FF! MU 2'7 1a INVENTORS ATTORNEY.

Patented 1.... 18,1949- FLAME SEALING APPARATUS Alfred G. H Witt, La Grange Park, and Sylvester F. Clemen Chicago, Ill., asslgnors to The Visk- -ing Corporation, Chicago, III;, a corporation of Virginia Application April 5, 1946, Serial No. 659,970

This invention relates to an apparatus for flame sealing. sheets of thermoplastic material in order to secure the edge of one sheet or layer of thermoplastic material to the" edge of another. It relates more particularly to bonding sheets or layers of thermoplastic material of the order of thickness of from 0.0002" to 0.03", al=- though it is within the scope of this invention to bond thicken sheets of thermoplastic material.

This invention is particularly adapted to bond and close the ends of thermoplastic tubes to form gas, moisture and waterproof bags or containers in which various articles may be'packaged. The

apparatus has been found satisfactory to close the ends of seamless tubes made from polyethylene, although it may be used to bond various other thermoplastic materials such as, by way of example but not by way of limitation, poly isobutylene, rubber hydrochloride, ethyl cellulose,

position, leaving a gas, moisture and waterproof beaded seam that is even stronger than the material of which the bag itself is formed.

In general, the machine consists of two endless steel bands which travel in contact with the article to be acted on. and carry it past the flame and out of the machine. The machine of this invention is illustrated as a double machine having means for feeding thermoplastic tubes and the like from either side. In the description, only one side will be described, since the other side is exactly alike, except that enough description will be given as is necessary to make clear how'the parts are related to each other.

Referring to the drawings:

machine with the feeding table and guard removed;

Figure 2is an end view of the machine taken from the right of Figure l, and shows clearly the feeding table and guard heretofore referred to;

Figure 3 is a partial section taken through the line 3-3 of Figure 1, and looking. in the direction 01 the arrows;

Figure 4 is a partial section taken through the 9 Claims. (Cl. 154-42) Figure is a side elevation of One Side Of cross piece Qa purpose of the pivot and 2 line 4-4 of Figure 1. and looking in the direction of the arrows; I

Figure 5 is a perspective view of the main frame of the machine; H

Figure 6 is a perspective view oi the gas burner of the machine;

Figure 7 is a partial section taken through the line 'l-l of Figure l, and looking in the direction of the arrows; and

Figure 8 is an end view of the'wheels support= lllg the endlessbelts showing the gear driving the same.

Referring to Figure 5, the frame consists of uprights it, ll, i2 and it. These uprights are connected with cross-pieces it, it, it and it, and with horizontal members it, it, 20 and ill. This frame may be welded together or cast in sections at ones option. Mounted on the horizontal members it and iil'are pillow blocks 22 andtt. Mounted on the uprights i0 and i l are pillow blocks 2t and 20 respectively. These pillow blocks form bearings for shafts which will hereinafter be described. Mounted on the horizontal pieces 26 and 26 is a shelf-like structure as which forms a support for the motor and reduction gear mechanism, which will hereafter be described. Mounted on the horizontal pieces it and it are cross-pieces it (see Figure 7). and 20 (see Figure l). Mounted on the crosspieces iii and 20 are upright members 29 and till (see Figures 1 and 7). Gross-members ti and 252 are secured to the top of the uprights lit and 30 respectively. Secured to the cross-members 8i and 32 respectively are upright members 33 and 3d. The upright members 29, t3, t0 and M, with the cross-members 3i and 32, form supporting means for various parts 01' the machine.

On the top of the uprights t3 and 0d are crosspieces 35 and 3% respectively. Bar-like members 3t, 30, 39 and (see Figures 1 and '7) are supported by the cross-members M, 32 and 8t, 3t respectively. The cross-members are welded to the bars. The bars 38 and 30 have their ends pivoted on a common pivot at. The end pieces of the bars 38 and 50 are secured together by a cross-piece will hereafter be described.

Mounted on each end of the longitudinal members 3!,39, 3t and i0 are grooved wheels tit, 05, t6 and 41. The grooved wheels it and it form a support for an endless metal belt t0 while the grooved wheels 46 and ii form a support for endless metal belt 49. The endless belts 48 and 49 areabout .018 of aninch thick and of an inch wide, and may be made of spring steel. Similar belts are mounted on companion wheels 44, 48', 48', and 41.-

Mounted on the longitudinal member 31 is bracket member 50, one end of which is split. There is a corresponding bracket on the longitudinal member 39, similar to 58, but not shown. These brackets form a support for an idler pulley which bears against the belt 48 to keep it taut while the roller mounted on the'corresponding longitudinal member 39 performs the same function for the opposite belt. A similar construction mounted on the top of the longitudinal member 38 supports a roller 52, the corresponding roller not being shown, which bears on the corresponding steel band which forms the other part of the double machine. The longitudinal members 31 and 39 are connected together by-cross-piece 53. Mounted on this cross-piece is an upright member 54 (Figures 1 and 3). the upright member 54 are secured two plates 55 and 55, and to the plate 58 is secured an upright member 51 which carries a cross-member 58 with two depending members 59 and 80 (Figure 3), each one carrying a guide plate 5!, 32 (see Figures 1 and 3). The member56, together with the guide plates iii, 82, form means for positioning the articles to be sealed so that the proper amount of the ends thereof are exposed to the flame. The amount of material exposed to the flame is from to %6 of an inch, depending upon the thickness of the material to be sealed.

Mounted on the upright member 33 are two wheels 63 and 84. Mounted on the upright member 34 are two wheels 65 and 58, 88 being beyond 65 and not shown. The two wheels 53 and 55 are adapted to press against the belts 48 and 49 to hold them together. This is accomplished by a flat bar 81 which is supported on spring-pressed plungers 68 and 59. These plungers are supported on the cross-members 8i and 32 respectively. The other side of the machine has a corresponding set of wheels, and a corresponding pressure plate, and spring-pressed plungers.

Mounted on the longitudinal members 38 and 48 are crossbars 18 and H. A plate 12 is downwaiily supported from the cross bars by means of members 13 and 14. The plate 12 forms an abutment for the spring-pressed bar 81 and tends to hold the belts 49, 48 pressed close against the article to be acted on as it passes through the machine. The other side of the machine is equipped with a corresponding plate and supports which tend to hold the other two bands on the opposite side of the machine in close relationship to the article being operated on on the opposite side of the machine. Y

A burner." (see Figures 1, 4 and 6) is adjustably mounted between the longitudinal members 31 and 39 and is held in proper relationship with the moving bands by the adjustment screws 18 and 11 (see Figure 4). The burner is connected to a source of gas and air by means of a pipe 19. It will be noted that the burner 15 has two rows of openings 80 and 8|, each row serving one side of the machine.

The ends of the bars 38 and 40, which have been described as being pivoted at 42 and joined by the crosspiece 43, are connected with the pivot 46 on which the end wheels 48 and the corresponding one on the other side (not shown) are mounted. A horizontal arm 82 is also pivoted at 48". An upright member 83, a horizontal member 84, and an upright member 85 form a U-shape continuation with 82. To the member 85 is secured a springpressed cam follower 85, guided in a bar 86', sup- To the upper part of ported on brackets, which isadapted to act on the cam 81. This cam 81 is supported by a shaft 88 mounted in the pillow blocks 24 and 25. The rotation of the cam tends to lift the articulated ends of the bars 38 and 48, with accompanying guide wheels for the steel bands, periodically to enable the attendant to feed the edge of the object to be acted on, such as an edge of a tubular plastic tube, past the guide member 8|, between the steel bands 48, 49, and against the abutment 51. Further rotation of the cam permits the wheels at the ends of the bars 38 and 48 to fall, thereby bringing the belts 48 and 49 in close contact with the article to be operated on.

Mounted on the shelf 26 is a combined motor reduction gear unit 89 of well-known construction. Mounted on the pillow blocks 22 and 23 is a shaft 98, to which is secured a sprocket 9|. which is driven by a chain from a sprocket 92 on shaft 93 of the reduction unit. Mounted on the shaft 90 is a toothed gear 94. The grooved wheel 41, with its companion wheel 41' (Figure 8) from the other side of the machine, are secured to a gear 95. Likewise, the grooved wheel 45, with its companion wheel from the other side of the machine, are joined together by a toothed gear 96. The gears 95 and 98 are adapted to mesh with each other, and the gear 94 is likewise adapted to mesh with the gear 96. Thus, the rotation of the shaft 98 by means of the motor drives the combined pulley units 45 and 41 in synchronism so that the belts 48 and 49 travel at the same speed. The shaft 88 carries a sprocket 91 which is driven by a chain 98 from the motor unit 89.

Each side of the double machine has a feeding table 99, Hill. The feeding tables are supported by the uprights H34 and I02 respectively. Beyond the feeding tables are inclined shields or guards $83 and i514. These shields tend to support the end of the tube grasped by the moving bands and offer less friction than if they were horizontal. Furthermore, they tend to prevent the unsealed ends of the tubes, and also the operators, from coming in contact with the moving parts of the machine.

One operation of the machine will now be described in the process of sealing tubes to make bags or pouches therefrom.

The burner is lit, the power turned on the machine, and the operator sitting at the feeding table 99 inserts one end of a tube from a supply of open-ended tubes on the table beneath the guide plate GI and up against the gauge 51 so as to expose the exact amount of material to be sealed by the flame. This operation is done while the cam 81, with its accompanying U-shaped members 82, 83 and 84, raises the wheel 48, with its accompanying steel band 49, out of contact with the band 48, as is shown in Figure 3. As the cam travels on its journey, it lowers the member 48, with its accompanying band 49, into intimate contact with the material and holds it firmly between the two belts 48 and 49. The movement of these belts, because the two pulleys 45 and 41 are being driven by the power unit, causes the tube to travel through the machine and brings the exposed end of the tube into contact with the flame coming out of the openings of the burner 15. .The spring-pressed plate 61, together with the stationary plate 12 and the two rollers 63 and 85, hold the steel belts closely together against the work, leaving only from to A of an inch of the end of the tube exposed to the action of the flame. The end of the tube being enclosed between the two metal belts 48 estates raise the upper belt at the, feed end of the me.

chine at predetermined intervals to permit into be inserted against the gauge and travel through the machine. The operator at the feeding table iilll performs a similar operation on the other side of the machine on each raising of the corresponding metal belt? The machine forms a uniform beaded seal on the end of the tube which has been passed through the flame, leaving a strong bag or pouch in which any article may be packaged.

'Since it is obvious that many changes and modifications can be made in the above-described details without departing from the nature and spirit of the invention, it is to be understood that the invention is not to be limited thereto except as set forth in the appended claims.

We claim:

1. An apparatus for flame sealing thin-walledthermoplastic tubing which comprises a pair of driven belts located one above the other and adapted to contact with each other, cam actuated means to separate said belts periodically at the feed end of the machineto'permit insertion of the tubing to be sealed between said belts, means and adapted to contact with each other, cam

actuated means to separate said belts periodically at the feed end of the machine to permit insertion of the tubing to be sealed between said belts, means to position said tubing between said belts whereby only a small portion oi the end of belts, a burner providing an open flame in the path of travel of the exposed end 01 said tubing whereby said end is sealed as it is conveyed through said flame by said belts, and means to hold said belts in close engagement with said tubing as it passes through the zone of action of said flame.

3. An apparatus for flame sealing thin-walled thermoplastic tubing which comprises a pair oi driven belts located one above the other and adapted to contact with each other, means to raise the upper belt at the feed end of the machine at predetermined intervals to permit insertion of thetubing to be sealed between said belts, .means to lower said upper raised belt into position whereby said tubing is gripped between said belts, and a burner providing an open flame in the path of travel 01 the end of said tubing whereby said end is sealed as it is conveyed through said flame by said belts.

4. An apparatus for flame sealing thin-walled thermoplastic tubing which comprises a pair of driven belts located one above the other and adapted to contact with each other, means to the tubing is exposed beyond the edges of the sertion of the tubing to be sealed between said belts, means to lower said upper raised belt into position whereby said tubing is gripped between said belts, a burner providing an open flame in the path of travel of the endoi said tubing whereby said end is sealed as it is conveyed through said flame by said belts, and means to hold said belts in close engagement with said tubing as it passes through the zone of action oi said flame.

. 5. An apparatus for flame sealing thin-walled thermoplastic tubing which comprises a pair oi driven belts located one above the other and adapted to contact with each other, means to raise-the upper belt at the feed end of the machine at predetermined intervals to permit insertion of the tubing to be sealed between said belts, means to lower said upper raised belt into position whereby said tubing is gripped between said belts, means to position said tubing between said belts whereby only. a small-portion oi the end ofthe tubing is exposed beyond the edges oi. the belts, and a burner providing an open flame in .the path of travel of the exposed end of said tubing whereby said end is sealed as it is conveyed through said flame by said belts.

6. An apparatus for flame sealing thin-walled thermoplastic tubing which comprises a pair or driven belts located one above the other and adapted to contact with each other, means to raise the upper belt at the feed end of the ma-' chine at predetermined intervals to permit insertion oi the tubing to be sealed between said belts, means to lower said upper raised belt into position whereby said tubing is gripped between said belts, means to position said tubing between said belts whereby only a small portion of the end of the tubing is exposed beyond the edges of the belts, a burner providing an open flame in the path of travel of the exposed and of said tubing whereby said end is sealed as it is conveyed through said flame by said belts, and means to hold said belts in close engagement with said tubing as it passes through the zone of action of said flame.

'7. An apparatus for flame sealing thin-walled thermoplastic tubing which comprises a pair of driven endless belts located one above the other with the lower flight of the top belt contacting the upper flight of the lower belt, means to alternately raise and lower the upper belt at the feed I end of the machine at predetermined intervals to permit insertion and gripping oi the tubing to be sealed by said belts, means to position said tubing between said belts whereby onlya small portion of the end of the tubing is exposed beyond the edges of the belts, and a burnerpro. viding an open flame in the path of travel of the exposed end of said tubing whereby said end is sealed as it is conveyed through said flame by said belts.

8. An apparatus for flame sealing thin-walled thermoplastic tubing which comprises a pair of driven endless belts located one above the other with the lower flight of the top belt contacting the upper flight of the lower belt, means to alternately raise and lower the upper belt at the feed end of the machine at predetermined intervals to permit insertion and gripping of the tubing to be sealed by said belts means to position said tubing between said belts whereby only a small portion of the endoi the tubing is exposed beyond the edges-oi the belts, a burner providing an open flame in the path of travel of the exposed end of said tubing whereby said end is sealed as it is conveyed through said flame by said belts, 'and means to hold said belts in close engagement with said tubing as it passes through the zone of action of said flame.

9. An apparatus for flame sealing thin-walled thermoplastic tubing which comprises a pair of driven endless belts located one above the other with thelower flight oi the top belt contacting the upper flight of the lower belt, means to alternately raise and lower the upper belt at the feed end of the machine at predetermined intervals to permit insertion and gripping oi the tubing to be sealed by said belts, means to position said tubing betweensaid belts whereby only a small portion of the end of the tubing is exposed beyond the edges of the belts, a burner providing an open flame in the path of travel of the exposed and or said tubing whereby said end is sealed as it is con- 2,300,914

Number assaaas veyed through said time by said belts. and means to hold said belts in close engagement with'said tubing as it passes through the zone of action of said flame. said belts separating at the g discharge end to release the sealed tubing and dis-.

charge it from the apparatus.

' ALFRED G. HEWITT.

svnvms'rm F.

naranancns or'rnn The following references are oi record in the file or this patent:

UNITED 811m PATENTS Name Date 1,361,970 Dickey Dec. 14, 1920 2,075,735 Loomls Mar. 30, 1937 2,224,017 Gurwick Dec; 3, 1940 2,379,381 Bombard June 26, 1940 Bllleb Aug. 7, 1946 

